EP0940945A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A method and apparatus for certification and safe storage of electronic documents
Assignee: AT&T Inc
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Filing: 1999-03-04
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Granted: —
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Expires: 2019-03-04
Abstract
Abstract An electronic document provided by a user is certified using cryptographic functions to create a document fingerprint which is then cryptographically signed together with a time stamp. The document which was certified is archived for safe deposit and later retrieval. The document fingerprint and time stamp are returned to the user as part of a document certificate. The document certificate can be used to verify the authenticity of copies of the original document and to establish the prior existence of the document. The filename of each document certificate can include a portion of the document fingerprint associated with an electronic document to enable a very efficient search of a set of document certificates to identify possible matches between document certificates and the electronic document being verified.
Inventors
- 👤 Mark Meier Rochkind
- 👤 Karl Andres Siil
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 23:07
CPC Classifications
H; H04; H04L; H04L63/00; H04L63/12; H04L63/123; G; G06; G06Q; G06Q20/00; G06Q20/38; G06Q20/389; H04L9/00; H04L9/32; H04L9/3247; H04L9/3263; H04L9/3297; H04L2209/00; H04L2209/60; H04L2463/00; H04L2463/103; H04L2463/121
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
72 words
A method for certifying and preserving an electronic document, comprising: (a) applying a first cryptographic hash function to the electronic
document to produce a document fingerprint; (b) applying a second cryptographic hash function to a document
certificate which includes the document fingerprint, a time stamp, and
a serial number to produce a document certificate fingerprint; (c) cryptographically signing the certificate fingerprint to produce a
digital signature; and (d) storing the electronic document.
Claim 2
Dependent Claim
22 words
The method of claim 1, wherein the serial number includes at least a portion
of the document fingerprint produced in step (a).
Claim 3
Dependent Claim
26 words
The method of claim 1, wherein the serial number includes at least a portion
of the document fingerprint produced in step (a) and the time stamp.
Claim 4
Dependent Claim
29 words
The method of claim 1, wherein the serial number includes at least a portion
of the document fingerprint produced in step (a), the time stamp, and a sequence
number.
Claim 5
Dependent Claim
18 words
The method of claim 1, wherein the serial number is used as a filename for
the document certificate.
Claim 6
Dependent Claim
48 words
The method of claim 1, wherein the serial number includes at least a portion
of the document fingerprint produced in step (a), the time stamp having a time
resolution, a sequence number reset every time resolution and a service identifier
indicating a processor used by a service provider.
Claim 7
Dependent Claim
63 words
The method of claim 1, wherein: the first cryptographic hash function applied in step (a) is a collision resistant
hash function, the second cryptographic hash function applied in step (b) is a collision
resistant hash function, and the cryptographic signing in step (c) uses a public-key encryption scheme
including a private key for cryptographic signing and its associated public key for
cryptographic verifying.
Claim 8
Dependent Claim
64 words
The method of claim 1, wherein: the first cryptographic hash function applied in step (a) is a MD5 hash
function, the second cryptographic hash function applied in step (b) is a MD5 hash
function, and the cryptographic signing in step (c) uses an RSA public-key encryption
scheme including an RSA private key for cryptographic signing and its associated
RSA public key for cryptographic verifying.
Claim 9
Dependent Claim
55 words
The method of claim 1, further comprising: (e) applying a third cryptographic hash function to the electronic
document to produce a second document fingerprint; the serial number including at least a portion of the first document fingerprint
produced in step (a) and at least a portion of the second document fingerprint
produced in step (e).
Claim 10
Dependent Claim
65 words
The method of claim 1, further comprising: (e) applying a third cryptographic hash function to the electronic
document to produce a second document fingerprint, the third
cryptographic hash function being the SHA-1 hash function; the serial number including at least a portion of the first document fingerprint
produced in step (a) and at least a portion of the second document fingerprint
produced in step (e).
Claim 11
Dependent Claim
21 words
The method of claim 1, wherein the storing step (d) further includes storing
the document certificate and its associated digital signature.
Claim 12
Dependent Claim
25 words
The method of claim 1, further comprising: (e) sending to the user the document certificate stored in said storing step
(d) and the digital signature.
Claim 13
Dependent Claim
18 words
The method of claim 1, further comprising: (e) deleting the electronic document stored in said storing step (d).
Claim 14
Independent Claim
138 words
A method for retrieving and authenticating an electronic document,
comprising: (a) obtaining the electronic document, a document certificate associated
with the electronic document and having a first document fingerprint,
and a digital signature associated with the document certificate; (b) applying a first cryptographic hash function to the document
certificate to produce a first document certificate fingerprint; (c) cryptographically verifying the digital signature to produce a second
document certificate fingerprint; (d) indicating, when the first document certificate fingerprint matches the
second document certificate fingerprint, that the first document
fingerprint and the certification time associated with the document
certificate are authentic; (e) applying a second cryptographic hash function to the electronic
document to produce a second document fingerprint; and (f) indicating, when the first document fingerprint matches the second
document fingerprint, that the contents of the electronic document are
authentic.
Claim 15
Dependent Claim
27 words
The method of claim 14, further comprising: (g) sending a request to a server for the electronic document and the
document certificate associated with the electronic document.
Claim 16
Dependent Claim
70 words
The method of claim 14, wherein said indicating step (f) includes: (i) comparing a hash value of a serial number included in a
filename of the document certificate with a corresponding
portion of the second document fingerprint; (ii) comparing, when the hash value and the corresponding
portion of the second document fingerprint compared in step
(f)(i) match, the first document fingerprint of the document
certificate with the second document fingerprint.
Claim 17
Dependent Claim
95 words
The method of claim 14, wherein said indicating step (f) includes: (i) comparing the second document fingerprint with a plurality of
filenames each filename corresponding to one document
certificate from a plurality of document certificates, each
filename including a hash value component of a serial number
associated with its document certificate; and (ii) comparing, when the hash value component of at least one
filename from the plurality of filenames matches a
corresponding portion of the second document fingerprint
compared in step (f)(i), the first document fingerprint of the
document certificate with the second document fingerprint.
Claim 18
Dependent Claim
90 words
The method of claim 14, wherein said indicating step (f) includes: (i) comparing the second document fingerprint with a plurality of
filenames each filename corresponding to one document
certificate from a plurality of document certificates, each
filename beginning with a portion of the first document
fingerprint; and (ii) comparing, when the hash value component of at least one
filename from the plurality of filenames matches a
corresponding portion of the second document fingerprint
compared in step (f)(i), the first document fingerprint of the
document certificate with the second document fingerprint.
Claim 19
Dependent Claim
63 words
The method of claim 14, wherein: the first cryptographic hash function applied in step (b) is a collision resistant
hash function, the second cryptographic hash function applied in step (e) is a collision
resistant hash function, and the cryptographic verifying in step (c) uses a public-key encryption scheme
including a private key for cryptographic signing and its associated public key for
cryptographic verifying.
Claim 20
Dependent Claim
64 words
The method of claim 14, wherein: the first cryptographic hash function applied in step (b) is a MD5 hash
function, the second cryptographic hash function applied in step (e) is a MD5 hash
function, and the cryptographic verifying in step (c) uses an RSA public-key encryption
scheme including an RSA private key for cryptographic signing and its associated
RSA public key for cryptographic verifying.
Claim 21
Dependent Claim
55 words
The method of claim 14, further comprising: (g) applying a third cryptographic hash function to the electronic
document to produce a third document fingerprint; the serial number including at least a portion of the second document
fingerprint produced in step (e) and at least a portion of the third document
fingerprint produced in step (g).
Claim 22
Dependent Claim
65 words
The method of claim 14, further comprising: (g) applying a third cryptographic hash function to the electronic
document to produce a second document fingerprint, the third
cryptographic hash function being the SHA-1 hash function; the serial number including at least a portion of the second document
fingerprint produced in step (e) and at least a portion of the third document
fingerprint produced in step (g).
Claim 23
Dependent Claim
25 words
The method of claim 14, wherein the electronic document, the document
certificate and the digital signature obtained in step (a) are obtained from local
storage.
Claim 24
Dependent Claim
36 words
The method of claim 14, wherein the electronic document, the document
certificate and the digital signature obtained in step (a) are obtained from a service
provider, who originally certified the electronic document, through a communication
network.
Claim 25
Dependent Claim
33 words
The method of claim 14, wherein the electronic document, the document
certificate and the digital signature obtained in step (a) are obtained from a remote
party through a communication network using electronic mail.
Claim 26
Dependent Claim
29 words
The method of claim 14, wherein the electronic document, the document
certificate and the digital signature obtained in step (a) are obtained from a remote
party through portable medium.
Claim 27
Independent Claim
109 words
A method for determining whether an electronic document is an authentic
copy based on a plurality of document certificates each having its own document
fingerprint, comprising: (a) applying a cryptographic hash function to the electronic document to
produce a first document fingerprint; (b) comparing the first document fingerprint to the document fingerprint
of at least one document certificate from the plurality of document
certificates; and (c) indicating, when the first document fingerprint matches the document
fingerprint of the at least one document certificate from the plurality
of document certificates, that the electronic document is an authentic
copy of the electronic document associated with the at least one
document certificate.
Claim 28
Dependent Claim
18 words
The method of claim 27, wherein the plurality of document certificates are
stored on a publicly accessible database.
Claim 29
Dependent Claim
18 words
The method of claim 27, wherein the plurality of document certificates are
stored on a limited access database.
Claim 30
Independent Claim
170 words
A method for determining whether a candidate electronic document is an
authenticate copy of an original electronic document using a document certificate
associated with the original electronic document, comprising: (a) obtaining the candidate electronic document, the document certificate
associated with the candidate electronic document and having a first
document fingerprint, and a digital signature associated with the
document certificate; (b) applying a first cryptographic hash function to the document
certificate to produce a first document certificate fingerprint; (c) cryptographically verifying the digital signature to produce a second
document certificate fingerprint; (d) indicating, when the first document certificate fingerprint matches the
second document certificate fingerprint, that the first document
fingerprint and the certification time associated with the document
certificate are authentic; (e) applying a second cryptographic hash function to the candidate
electronic document to produce a second document fingerprint; and (f) indicating, when the first document fingerprint matches the second
document fingerprint contained within the document certificate, that
the candidate electronic document is the authentic copy of the original
electronic document.
Claim 31
Independent Claim
105 words
An apparatus for certifying and preserving an electronic document,
comprising: a processor; a first memory connected to said processor, said first memory storing the
electronic document and storing a plurality of instructions adapted to be executed by
said processor to: (a) apply a first cryptographic hash function to the electronic
document to produce a document fingerprint; (b) apply a second cryptographic hash function to a document
certificate which includes the document fingerprint, a time
stamp, and a serial number to produce a document certificate
fingerprint; (c) cryptographically sign the certificate fingerprint to produce a
digital signature; and (d) store the electronic document in said memory.
Claim 32
Independent Claim
76 words
An apparatus for certifying and preserving an electronic document,
comprising: means for applying a first cryptographic hash function to the electronic
document to produce a document fingerprint; means for applying a second cryptographic hash function to a document
certificate which includes the document fingerprint, a time stamp, and a serial
number to produce a document certificate fingerprint; means for cryptographically signing the certificate fingerprint to produce a
digital signature; and means for storing the electronic document.
Claim 33
Independent Claim
178 words
An apparatus for certifying and preserving an electronic document to enable
a user to subsequently authenticate contents of and certification date of the electronic
document, comprising: a processor; and a memory connected to said processor, said memory storing a plurality of
instructions adapted to be executed by said processor to: (a) obtain the electronic document, a document certificate associated
with the electronic document and having a first document fingerprint,
and a digital signature associated with the document certificate; (b) apply a first cryptographic hash function to the document certificate
to produce a first document certificate fingerprint; (c) cryptographically verify the digital signature to produce a second
document certificate fingerprint; and (d) indicate, when the first document certificate fingerprint matches the
second document certificate fingerprint, that the first document
fingerprint and the certification time associated with the document
certificate are authentic. (e) apply a second cryptographic hash function to the electronic
document to produce a second document fingerprint; (f) indicate, when the first document fingerprint matches the second
document fingerprint, that the contents of the electronic document are
authentic.
References Cited (Backward Citations)
No citation records indexed.
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